Fabric belt for papermaking machine



March 14, 1967 K. v. KRAKE 3,309,265

FABRIC BELT FOR PAPERMAKING MACHINE Filed Sept. 27, 1963 v, 2Sheets-Sheet l A M, 32%? K. v. KRAKE FABRIC BELT FOR PAPERMAKING MACHINEfivian's 2 Sheets-Sheet Filed Sept. 27, 19m:

u nu A h WH w|i mi H n Huh & i M 4 1 i w ii Uit My invention relates topapermaking machines, particularly of the Fourdrinier type, and, moreparticularly, to improved Fourdrinier fabrics for use in such machines.

Fourdrinier fabrics for forming paper webs by drainage of water frompaper stock applied onto the fabrics commonly comprise warp strandsextending in the machine direction (that is, in the direction in whichthe Fourdrinier fabric is moved as stock is applied onto the fabric)interwoven with shute strands extending in the cross machine direction.

The weaving process is necessarily quite time consuming and expensivedue to the fact that each of the shute strands must pass between variousones of the Warp strands and each shute strand must be put into placeindividually.

It has been proposed in a prior application of Winterton U. Day, Ser.No. 97,492, filed Mar. 22, 1961, now Pat. No. 3,164,514, that suchFourdrinier fabrics be made of cross laid wires, that is, a set ofparallel, spaced warp wires extending in the machine direction and aplurality of parallel, spaced shute wires extending in the cross machinedirection and simply laid onto one side of the series of Warp wires,with the shute and Warp wires being welded together. This constituted asubstantial improvement on the prior interwoven fabrics, being muchsimpler in construction and, therefore, considerably cheaper tomanufacture.

It is an object of the present invention to provide cross laid weldedfabrics which are of the basic type illustrated in the Winterton U. Dayprior application and which constitute improvements by each being madeup of a set of filaments or wires of nonround cross section havingsurfaces extending other than at 90 degrees with respect to the planeformed by the other set of filaments or wires for the purpose ofchanging the drainage of white water from the paper stock applied ontothe fabric and thereby changing the characteristic of the resultingpaper web.

The invention consists of the novel constructions, arrangements, anddevices to be hereinafter described and claimed for carrying out theabove stated objects and such other objects as will be apparent from thefollowing description of preferred forms of the invention, illustratedwith reference to the accompanying drawings, wherein:

FIG. 1 is a fragmentary, schematic, side view of a Fourdrinier webforming machine including a Fourdrinier forming fabric movably trainedin the form of a loop about a plurality of supporting rolls and alsoincluding a stock inlet for applying stock onto the fabric;

FIG. 2 is a longitudinal sectional view on an enlarged scale of thestock inlet;

FIG. 3 is a fragmentary plan View of the forming fabric used in themachine illustrated in FIGS. 1 and 2;

FIG. 4 is a sectional view of the forming fabric taken on line 4-4- ofFIG. 3;

FIGS. 5, 6, 7 and 8 are views similar to FIG 4 of modified forms offorming fabric constructed according to the principles of the invention;and

FIG. 9 is a plan view of another modified form of forming fabricconstructed according to the principles of the invention.

Referring now to the drawings, and in particular to FIGS. 1 and 2, theillustrated papermaking machine may be seen to comprise an endlessfabric belt 10 positioned "ice about a breast roll 11, a couch roll 12,table rolls 13 and a guide roll 14. A vacuum box 15 is positionedbeneath the belt 10 and in contact with it.

A headbox 16 having a slice 17 is positioned above the belt 16. Theheadbox 16 may be of any suitable type, but is preferably one that isparticularly suitable for pressure forming. As shown, the headboxcomprises a turbulizing driven roll 18 disposed in a cylindrical cavity19. A stock inlet conduit 29 is connected to the cavity 19, and athrottle plate 21 is adjustably positioned adjacent the roll 18 withinthe conduit. The inlet is provided with an apron plate 22 and the slice17 has an end lip 23 which terminates adjacent the breast roll 11. Thebelt 10 extends around the breast roll 11 and in contact with the lip23, as shown particularly in FIG. 2.

A tray 24, which is adapted to collect the white water, i.e., the liquidwhich drains through the fabric 10 during the web forming operation, isdisposed between the upper and lower runs of the fabric 10, asillustrated. This tray is arranged to discharge into a mixing tank 25normally maintained about three-fourths filled with paper stock, whichis a fluent mass of fibers and water. Fresh water for makeup purposesmay be added through the pipe 26; and additional stock, as is necessaryto maintain the proper consistency or fiber concentration of the fluidsuspension of stock delivered to the web forming region in the inlet 16,is added through a second inlet pipe 27.

The bottom of the mixing tank 25 is inclined, as shown, and a main flowline 28 connects to the tank at the lower end thereof. The main flowline 28 includes a branch extension 29 having a valve 30 therein for usein draining the mixing tank, and the main flow line 28 also connectswith the inflow side of a stock or fan pump 31, which is the principalmeans relied upon to deliver stock to the Web forming region of themachine.

The outlet of the fan pump 31 is connected to the conduit 20 in theheadbox 16 by suitable piping indicated generally at 32. Included inthis piping is an automatically operable pressure regulating valve 33and a transition section 34 which converts the circular cross sectionalstream delivered by the fan pump 31 and piping 32 to a stream ofrectangular outline. The piping 32 also includes a bypass line 35 whichconnects the outlet side of the fan pump 31, upstream of the pressureregulator valve 33, with the mixing tank 25. A shutoff valve 36 isprovided in the bypass line 35. Suitable showers or sprays, indicatedgenerally at 37, are provided for effecting continuous cleaning of therolls and fabric, in accordance with usual papermaking practices.

The particular breast roll 11 that is illustrated is of the open surfacetype and comprises a cylindrical shell 38 having a plurality ofoutwardly projecting rings 39 fixed thereon. The rings 39 support aplurality of vanes 40, and the open surface of the roll 11 is formed bya ribbon 41 that is countersunk endwise into the vanes 40. The fabric 10is driven by means of any suitable prime mover connected to any of therolls supporting the fabric 10, and the turbulizing driven roll 18 isalso preferably driven by any suitable prime mover (not shown) so as topromote turbulence in the stock passing onto the fabric 10.

A conventional felt section is disposed behind the Fourdrinier sectionjust described, and the felt section may comprise a felt 42 in the form,of a loop that extends around a plurality of rolls including the roll43 which has a nip with the couch roll 12.

In operation, the fan pump 31 draws stock from the mixing tank 25 anddischarges it under pressure from the piping 32 into the conduit 20. Apart of the stock that passes through the conduit 20 is propeled aroundwithin the cylindrical cavity 19 by the driven roll 18,

and turbulence and dynamic energy are thus added to the stock prior toits passage onto the fabric 19. A part of the stock from the conduit 2!)discharges onto the fabric and breast roll 11 in a web forming regionbetween the apron 22 and lip 23, and white water drains from the stockthrough the fabric and into the breast roll. The vanes 40 of the breastroll are preferably forwardly bent, as shown, so that they retain a partof the water draining from the stock, so that this water is thrown outof the breast roll 11 between the upper and lower passes of the fabric10 for helping to dewater the stock to form a web W. White watercontinues to drain through the fabric 10 as the fabric moves over thetable rolls 13 and suction box to the couch roll 12; and the table rolls13 and suction box 15 all have a vacuum effect for helping to dewaterthe paper web W. The paper web W is transferred from the fabric 10 ontothe felt 42, and the felt section of the machine functions as doconventional felt sections for additionally dewatering the web W and fortransferring the web to a conventional drier section (not shown).

Referring to FIG. 3, the fabric 10 may be made up of a plurality of warpstrands or filaments 50 which extend in the machine direction, that is,in the direction of movement of the fabric it which is indicated by thearrow A in FIG. 3, and a plurality of shute strands or filaments 51which extend in the cross machine direction. The strands 50 are equallyspaced from each other, and the strands 51 are likewise equally spacedfrom each other, although it will be understood that the strands 50 maybe spaced from each other at different distances than the strands 51.The strands 51 in the illustrated form of fabric extend at right anglesto the strands 50 and overlie all of the strands 50 so that the strands51 are on the papermaking side of the cloth 10, that is, the upper sideof the run of the fabric 10 between the rolls 11 and 12 which comes intocontract with the lip 23 as the fabric 10 moves.

The strands 50 are round metal wires, such as of brass or bronze. Thewires 51 may be made of the same metal and are triangular in crosssection as illustrated in FIG. 4, each of the wires 51 having planefaces 52, 53, and 54. The face 54 of each of the wires 51 is in contactwith the warp wires 50, and the wires 51 are suitably welded to thewires 56 on the edges of the faces 54. The faces 52 and 53 extend atacute angles with respect to the plane aa of the fabric throughcorresponding points of either of the sets of wires, and the faces 52and 53 meet at apices that are remote from the wires 50.

The modified form of fabric illustrated in FIG. 5 comprises shute wires51a that are also triangular in cross section and have plane surfaces52a, 53a, and 54a. The apex of the triangle of each of the wires incross section formed by the sides 52a and 53a is in contact with thewarp wires 559a, and each of the wires 51a is welded to each of thewires 543a along the apex formed by the surfaces 52a and 53a. The faces52a and 53a extend at acute angles to the plane aa of the fabric asshown.

The modified form of fabric illustrated in FIG. 6 comprises the warpwires 56b and shute wires 51b. The shute wires 51b each have a crosssection in the form of a parallelogram and have plane sides 55, 56, 57,and 58. The plane sides 57 are in contact with the Warp wires 50b, andthe wires 5112 are welded at the edges of the plane sides 57 to thewires 50b. The sides 55 and 58 of the wires 51b are at acute and obtuseangles with respect to the plane aa of the fabric, so that the wires 51blag or extend backwardly from the direction A of movement of the fabric.

The modified form of fabric illustrated in FIG. 7 comprises the warpwires 56c and shute wires 51s. The shute wires 51c in cross sec ion formfive plane sided figures with plane surfaces 59, 66, 61, 62, and 63. Theplane surfaces 59 are in contact with the wires Stle, and the wires 51care welded to the wires Site at the edges of the surfaces 59. Thesurfaces 60 and 63 extend at right angles to the plane aa of the fabric;and the plane surfaces 61 and 62 extend at acute angles to the plane a-aand form an apex 64 which projects upwardly on the papermaking side ofthe fabric.

The modified form of fabric illustrated in FIG. 8 comprises the warpwires 50 and shute wires 51 The shute wires 51 in cross section formparallelograms having plane sides 65, 66, 67, and 68. The plane surfaces65 are in contact with the warp wires 50 and the wires 51] are welded tothe Wires SW at the sides of the plane surfaces 65. The surfaces 67extend parallel with the plane aa of the fabric, and the surfaces 66 and68 are at acute and obtuse angles with respect to the plane aa so thatthe wires 51 lean in the direction of movement A of the fabric.

The advantage of making the shute wires in the various forms of fabricnon-round in cross section is to be able to better control the fiow ofwhite water between the shute wires and thus to control better the layof fibers in the finished web and to prevent stapling or fixing of thefibers with respect to the shute wires. The advantage, in particular, ofthe inverted triangular shape of shute wires, as illustrated in FIG. 5,is to provide the least amount of stapling while yet providing goodwhite water drainage. The paper fibers have a certain stiffness, and dueto this stiffness, they are not able to bend around the triangular shutewires 51a to fix themselves with respect to the shute wires. It will beobserved that the drainage openings between the triangular shute wires51a opens downwardly or inwardly with respect to the fabric so that thedrainage openings increase in width inwardly of the wire. While theopenings are not strictly in the form of a vena contracta, neverthelessthey do open inwardly or downwardly of the wire and provide littleimpedient to the flow of the water through the fabric which helps inpaper formation. The advantage of the form of fabric illustrated in FIG.4 having the base surfaces 54 of the triangular shapes in contact withthe warp wires 50 is to give the maximum amount of white water drainage.The advantages of the forms of fabric shown in FIGS. 6 and 8 are toprovide horizontal lines in the paper Web and to control crossdirectional stiffness and strength of the finished web. With respect tothe fabric shown in FIG. 6, in which the shute strands 51b lag in thedirection A of movement of the fabric, this configuration of shutestrands allows the white water to more easily flow and be drainedbetween the shute strands 5112, the flow being in the directionindicated by the arrow 69.

The forms of fabric having plane surfaces of the shute wires in contactwith the Warp wires are generally the types most easily welded; since,if electric resistance welding, for example, is utilized, there aregreater surfaces of the warp wires and shute wires in contact that maybe bonded together. Such forms of fabric are illustrated in FIGS. 4, 6,7 and 8.

Although I have specifically mentioned electric resistance welding forwelding the various wires of the fabrics together, other metal joiningmethods may also be used, such as brazing, thyratron welding, or evensoldering. Since better weld joints are provided with certain types ofwelding if larger area surfaces are in contact, it may be desirable tomake each of the warp wires of the various embodiments in the form of aribbon of rectangular cross section. Also, although I have referred tothe warp and shute filaments as being of metal, it will be apparent thatthese filaments can instead be made of synthetic or organic material;and, in this case, the strands can be fastened together by means of asuitable adhesive, such between the lip 23 and the apron 22 tend to turnparallel with the transversely extending strands 51, 51a, etc. Theresulting web, therefore, is one that has an increased strengthtransversely as compared to webs that are formed on conventional wovenwires that have both the warp and shute strands substantially in thesame plane. The elevated transversely extending strands 51, 51a, etc.have another advantageous function, namely, of providing a scrapingaction on the end of the lip 23, so as to assure that there is no undueaccumulation of fibers behind the lip 23 with resulting poor and unevensheet formation.

Although it will be obvious that the dimensions of the filaments 50, 51,etc. may vary; if it is desired to make a lightweight tissue, the warpwires and the shute wires may, for example, have thicknesses of about.00775 inch and .0095 inch, respectively. In this case there may beabout 70 warp wires and 52 shute wires to the inch. The size of theopenings looking directly down on the fabric may vary accordingly withthe spacing and sizes of the filaments, but may, for example, be about.0065 inch x .0097 inch for tissue. Shute wires 51, 51a, etc. would thusbe spaced about .0065 inch in the machine direction; while in the crossdirection, the distance between adjacent warp wires would be about .0097inch.

The forms of fabric previously described include strands that extend atright angles to each other. It will be obvious that the strands insteadmay be made to extend at acute angles with respect to each other, suchas the strands 50g and 51g making up the fabric illustrated in FIG. 9.The strands 50g may be either round or of rectangular cross sectionsimilar to the other w-arp strands, and the shute strands 51g may haveany of the cross sections previously described for the shute strands.

I wish it to be understood that the invention is not to be limited tothe specific constructions and arrangements shown and described, exceptonly insofar as the claims may be so limited, as it will be apparent tothose skilled in the art that changes may be made without departing fromthe principles of the invention.

What is claimed is:

1. An endless fabric belt for Fourdrinier type papermaking machineswhich is adapted to be supported by and to travel in a certain directionover a plurality of spaced rotatable rolls and to receive and drain afluent mass of fibers and water to form a paper web on the belt, saidbelt comprising a first set of filaments extending parallel to eachother and longitudinally of the belt and a second set of filaments alldisposed on the same side of the belt and extending parallel to eachother and crosswise of the belt in contact with and all at a certainangle to the filaments of said first set, the filaments of each of saidsets being solid in cross section and being equal in transversedimension and being equally spaced and the filaments of said two setsbeing bonded together at intersections of the filaments, the filamentsof said second set being nonround in cross section and havingsubstantially plane surfaces which lie at acute angles with respect tothe plane of the belt.

2. An endless fabric belt for Fourdrinier type papermaking machines asset forth in claim 1, each of said second set of filaments having across section in the form of a triangle with the base of the trianglebeing disposed in contact with said first set of filaments.

3. An endless fabric belt for Fourdrinier type papermaking machines asset forth in claim 1, each of said second set of filaments having across section in the form of a triangle with the apex of the trianglebeing in contact with said first set of filaments.

4. An endless fabric belt for Fourdrinier type papermaking machines asset forth in claim 1, said second set of filaments each having a crosssection in the form of a parallelogram, opposite sides of which haveacute and obtuse included angles with the plane of the belt, anotherside of the parallelogram being in contact with said first set offilaments.

5. An endless fabric belt for Fourdrinier type papermaking machines asset forth in claim 1 in which said second set of filaments each has across section with two plane sides extending substantially at rightangles to the plane of the belt and another plane side in contact withsaid first set of filaments and two more plane sides that meet at anapex opposite said plane side in contact with said first set offilaments.

6. An endless fabric belt for Fourdrinier type papermaking machines asset forth in claim 1 in which said second set of filaments each has across section in the form of a parallelogram with two opposite sides ofthe parallelogram leaning in the direction of movement of said belt.

7. An endless fabric belt for Fourdrinier type papermaking machines asset forth in claim 1 in which said second set of filaments each has across section in the form of a parallelogram with two opposite sides ofthe parallelogram leaning opposite to the direction of movement of saidbelt.

References Cited by the Examiner UNITED STATES PATENTS 3,158,984 12/1964 Butler 57144 3,164,514 1/1965 Day 162348 FOREIGN PATENTS 457,194 6/1949 Canada.

5,647 of 1828 Great Britain.

DONALL H. SYLVESTER, Primary Examiner.

J. H. NEWSOME, Assistant Examiner.

1. AN ENDLESS FABRIC BELT FOR FOURDRINIER TYPE PAPERMAKING MACHINESWHICH IS ADAPTED TO BE SUPPORTED BY AND TO TRAVEL IN A CERTAIN DIRECTIONOVER A PLURALITY OF SPACED ROTATABLE ROLLS AND TO RECEIVE AND DRAIN AFLUENT MASS OF FIBERS AND WATER TO FORM A PAPER WEB ON THE BELT, SAIDBELT COMPRISING A FIRST SET OF FILAMENTS EXTENDING PARALLEL TO EACHOTHER AND LONGITUDINALLY OF THE BELT AND A SECOND SET OF FILAMENTS ALLDISPOSED ON THE SAME SIDE OF THE BELT AND EXTENDING PARALLEL TO EACHOTHER AND CROSSWISE OF THE BELT IN CONTACT WITH AND ALL AT A CERTAINANGLE TO THE FILAMENTS OF SAID FIRST SET, THE FILAMENTS OF EACH OF SAIDSETS BEING SOLID IN CROSS SECTION AND BEING EQUAL IN TRANSVERSEDIMENSION AND BEING EQUALLY SPACED AND THE FILAMENTS OF SAID TWO SETSBEING BONDED TOGETHER AT INTERSECTIONS OF THE FILAMENTS, THE FILAMENTSOF SAID SECOND SET BEING NONROUND IN CROSS SECTION AND HAVINGSUBSTANTIALLY PLANE SURFACES WHICH LIE AT ACUTE ANGLES WITH RESPECT TOTHE PLANE OF THE BELT.